1. Field of the Invention
The present invention is related, generally, to vehicle twist axle assemblies.
2. Related Art
A twist beam rear axle suspension assembly, also known as a torsion beam axle, is a type of automobile suspension system including a pair of trailing arms, each of which is coupled with a wheel of a vehicle, and a twist beam which extends transversely between the trailing arms. During operation of the vehicle, the twist beam deforms in a twisting movement when one of the wheels moves relative to another, such as during vehicle body roll or when one of the wheels encounters, for example, a pothole or an obstacle in a road. The twisting movement of the twist beam absorbs this movement to make the ride more comfortable for occupants in the vehicle body.
In general, it is desirable to provide the twist beam with a pair of regions with a relatively increased stiffness at the ends of the twist beam and a relatively reduced stiffness in the longitudinal middle region of the twist beam. One approach to providing the twist beam with a middle region of reduced stiffness and end regions of increased stiffness is to form the twist beam of a tube and crush the tube into a U or V shape in the middle region. However, this process may be difficult to implement and may require one or more post-shaping heat treating operations which increase the cost of the resulting twist beam. Another approach is to stamp the twist beam to its shape and then to weld brackets to the longitudinal ends. Under this approach, the welded brackets provide the increased stiffness in the end portions.